In the semiconductor industry, dicing machines are used for cutting semiconductor wafers or packaged semiconductor devices along a lattice of cutting lines. The cutting lines define boundaries between individual integrated circuit (IC) units. Dicing is also known as singulation or die cutting. A dicing machine includes a number of components including a chuck station, for holding a workpiece being cut, and a cutting means including a spindle and a blade rotatably mounted on the spindle.
As the unit size of IC units in a wafer or package strip becomes small (of the order of 1 mm or below), the IC unit count per unit area, as well as the number of cutlines, of the wafer or package strip is increased. Accordingly, a longer dicing time is needed for each wafer or package strip and the units per hour (UPH) of the dicing machine is decreased.
In previously proposed dicing machines, it has been attempted to increase the UPH by providing additional chuck tables or additional blades. For example, in Japanese publication no. JP2007080897A of DISCO Corporation, two chuck tables are provided. A dual cutting means is used to dice a wafer loaded to one of the chuck tables while a second wafer is aligned, loaded to the other chuck table and prepared for dicing.
Although this improves the efficiency of processing, there is still a bottleneck when the unit size is small. Wafers or package strips with small units on board require long cutting times, perhaps up to 3-5 minutes for each workpiece. On the other hand, the typical loading process for a workpiece takes 20-30 seconds. Accordingly, the loading process of the next workpiece is finished long before the cutting is finished for the current workpiece. The chuck station & loading mechanism can be idle for over 80% of the time, thus leading to inefficiency.
It would be desirable to provide a singulation apparatus and method which can efficiently handle wafers or packages with small unit size, or which at least provides a useful alternative.